I have one disk partitioned into two logical drives, C and D. There is no unallocated space. I need to add space to C: so I want to use some space from D (plenty is available).

How can I do this without losing data on D:?

This is a Windows machine.

5 Answers 5


Assuming you use some kind of partition editor (such as GParted), when you perform a resize operation on D to create some unallocated space, it will adjust whatever files are in it to make sure you don't lose anything.

It's not like it will just cut a slab off the end of it without thinking twice. =]

  • 2
    Have good backups first. I RARELY have issues with gparted, but I have had some problems in the past. NEVER play with partitions without making a good backup first. Commented Aug 28, 2009 at 22:21
  • Agreed. It really stinks to find yourself with corrupted file systems afterward!
    – Ryan Lewis
    Commented Aug 28, 2009 at 22:28

Why take the risk of repartitioning? I strongly encourage anyone who is low on space to review the following web site - it contains a list of 20+ things to check on and clean off the C: drive. (Assuming this is a server, it usually alleviates the problem with virtually zero risk and less time than repartitioning software.



Partition resizing is in most cases relatively simple and rather safe, however BACKUP ALL your valuable data.

1) You would need live Linux CD, for instance Knoppix 5.3.1 DVD (but not 6.0.x). You can download it from the net or buy it anywhere for few $$.

2) It is very important to defragment both Windows partitions.

3) After defragmentation is complete insert you DVD disk and reboot computer (you may need to change BIOS setup {boot options, etc.} in order to start Knoppix from the disk).

4) Click letter K located in the bottom left corner of the screen and look for QTParted program.

5) Select your disk drive (/dev/hdX) and then select the second partition. Reduce it using graphical slider and then click icon to save changes. Wait for a moment. If you don't get any error messages then it's almost over.

7) Reboot computer, start Knoppix and run QTPArted once again. This time try to enlarge first partition and save changes. Reboot.

8) Reboot computer, remove DVD disk and let Windows start. It won't like changes that you've made but don't bother it.

9) Select my Computer and check actual partition sizes.

P.S. If your second partition (disk D) is located on extended partition (labeled as /dev/hdX6 or more in QTParted) this method will not work.


Beware: Repartitioning the C drive may cause the computer to become unbootable. In any case, some Windows files are unmovable, and are unhelpfully allocated by Windows at the end of the disk, so that one can only shrink C up to a limit.
If you're running Vista, the recommended way to resize disks is by click-right on Computer / Manage / Disk Management, then click-right on the partition and do Extend/Shrink Volume.
When shrinking, try first to defragment the partition so as to move all files to its beginning. Some good free defragmenters are Defraggler and Eusing Free Registry Defrag.
When you have some free space, you may "slide" a partition around by using Paragon Partition Manager Express, which you can also use to resize partitions.
Don't erase partitions that you don't recognize, since one might be the restore partition pre-created by your computer manufacturer.
Don't forget to backup ALL your data before doing any such manipulations! You can easily lose all data, so it's advised to take an image copy of at least your C drive, to avoid re-installing Windows.


Tools like PartitionMagic should be able to handle this problem easily. I've used PM in the past with plenty of ease. Unfortunately, I also used PM once and then had to re-install Windows and everything else all over again.

But Windows has a neat trick that you might consider to be interesting. In the "Computer Management console you can go to "Disk management" and change the drive letter. This feature also allows you to assign a disk to a path instead! So you could assign "C:\Data" to your D: drive and remove the D: completely. It would still be two disks but within C:\Data you have all the disk space of your D: drive while the rest uses the capacity of your C: drive. There's just a risk when you want this to contain e.g. your "Program files" folder or your Documents folder. If you'd redirect a folder that's critical for Windows during start-up and login then you could end up re-installing Windows again. Still, this disk-behind-a-folder technique can have plenty of purposes.

So, back up now!

One note about PartitionMagic, though. I purchased my 8.0 version about 5 years ago. It still is the most recent version so there's no guarantee that it will work with Vista or Windows 7 and maybe it won't even work with an up-to-date XP version! When will you know if it works? Well, either the repartitioning succeeds or you have to re-install Windows.

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